Gracilaria is common in this hobby and is often used as food for Tangs/Angles,etc...
Its nutrient uptake rate/growth rate is much slower than Chaeto and is not a replacement.. But if you want to produce your own macros for fish food then its an excellent choice..
Codium is a colder water species that doesn't do well in the temperatures most reefers keep their tanks.. It isn't a replacement for Chaeto either..
Cheato is intended for fast/easily controlled nutrient reduction.. Most "display" macros like Codium could be are for visual aspects,etc...While "food" macros like gracilaria are for well.. food